Electronic structure calculations based on density-functional theory with the generalized gradient approximation for 406 double perovskites La 2BB′O6 have been performed using the accurate full-potential linearized augmented plane wave method. La2 VTcO 6 and La2 VCuO6 are found to be candidates of half-metallic (HM) antiferromagnets (AFM) among the 406 ordered double perovskites La2 B B′ O6 with all the possible B and B′ pairs from all the 3d, 4d, and 5d transition metals have been considered. Furthermore, the HM-AFM state in La2 VTcO6 and La2 VCuO6 survive the full lattice constant and atomic position optimizations which were carried out using the frozen-core full-potential projector-augmented wave method. In addition, the GGA+U electronic structure calculations have also been performed and the HM-AFM state still remains. Their AFM state is attributed to both the superexchange and generalized double exchange mechanisms via the B(t2g) -O (2pπ) - B′ (t2g) coupling, and the latter could also be the origin of their HM.
|期刊||Physical Review B - Condensed Matter and Materials Physics|
|出版狀態||已發佈 - 2009 十二月 17|
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